Method of melting metal



1959 R. TRIPMACHER ETAL 2,873,102

METHOD OF MELTING METAL Original Filed Nov. 24, 1953 2 Sheets-Sheet 1FIG].

26 III l5 l6 15 Tl g L '67 21 a v j i I? I |9 I 7 V HI I V INVENTORRICHARD TRIPMACHER KARL LE UPOLD ATTORNEY 1959 R. TRIPMACHER EI'AL2,873,102

METHOD OF MELTING METAL Original Filed Nov. 24, 1953 2 Shets-Sheet 2FIG. .3.

INVENTORS RICHARD TRIPMA CHER KARL LE UPOLD BYMM ATTORNEYS United StatesPatent METHOD OF MELTING METAL Richard Tripmacher and Karl Leupold,North Rhine- Westphalia, Germany Continuation of application Serial No.394,154, Novem- 4 Claims. (Cl. 263--52) The present invention relates toimproved method of melting metal in an oscillating furnace or the like,and, more particularly, for melting shavings and wastes of light metaland light metal alloys in a simple, etficient, and economical manner.

This application is a continuation of our copending application, SerialNo. 394,154, filed November 24, 1953, now Patent No 2,783,990, datedMarch 5, 1957.

In the methods heretofore employed, it has been customary to bring thewaste material which is to be fed into the melting furnace into a feedchamber for the purpose of rapidly melting the metal. This feedorforechamber communicates with the melting chamber and the liquid metalis circulated continually through it from the melting chamber by meansof a pump. Due to this circulation of the liquid metal through thefreshly charged material to be melted, the high heat content of theliquid metal is transferred directly to the fresh material to be melted,so that circulation of the liquid metal through the feed chamber and theexcess heat of the melting chamber, which is heated continuously, iseconomically utilized and a rapid melting of the material is produced.

Such a circulation of the molten metal by means of pumps is expensive,sinceit requires not only a continuous supervision of the metalcirculation pumps but also the expense of supervising and maintainingthesepumps in proper operative condition. It has been found that nomatter how carefully such pumps are constructed, they are stronglyattacked by the hot metal and have to be frequently changed andrepaired. This results not only in high operating costs but also infrequent interruptions and inspections.

Accordingly, an important object of the present invention is to providean eificient and improved method of melting the material, such as lightmetal and metal alloys, by means of melting the sensitive metal ormaterial in an oscillating furnace without directly subjecting the freshmetal to either the high temperature of the waste gases or the heatingflame. This is accomplished by initially placing the material to betreated into a feed chamber which communicates on opposite sides withspaced melting chambers, heating the material in the melting chambersand oscillating or rocking the furnace so that the fresh material,introduced into the feed chamber, is brought into constant contact withthe molten metal as the latter circulates from one melting chamber tothe other through the feed chamber during the oscillating movement ofthe furnace. The furnace is rocked about a central axis and on oppositesides of the feed chamber, so that the feed chamber communicates withboth the melting chambers substantially in the transverse axis of swingof the furnace. The burners are located in each of the melting chambers,so that neither the flames nor the hot waste gases are brought in directcontact with the fresh metal or material.

A further object consists in covering the molten metal in the meltingchambers with a purifying salt or the like,

so as to isolate the molten metal from the combustion gases.

A still further object consists in submerging or dipping the freshmaterial in the feed chamber under the molten metal as the latter passesthrough the feed chamber, so as to insure intimate contact of thefresh'material with the molten metal.

The melting furnace is rocked or oscillated 'at. regular intervals, byany suitable means, so that the hot liquid 'or molten metal washesthrough the material freshly brought into the feedchamber and submergedunder the surface of the molten metal. Thus, the fresh materialisconstantly being mixed with the molten material and quickly preheatedand melted during the oscillating movement of the molten metal as it istransferred alternately from one melting chamber to the other.

In order to obtain a positive and thorough mixing of the fresh materialwith the molten material during the rocking movement of the furnace inaccordance with the present method, the feedchamber is arranged so thatit divides the melting furnace into two melting chambers, and is onlyconnected with the melting chambers by two connecting openings oralternately this division may be made by a separating wall connected tothe feed chamber. By use of such a separating wall, the feed chamber canalso be arranged outside the actual melting furnace. Referring to thedrawings, in which is shown a preferred form of oscillating furnace forcarrying out the present method:

Figure 1 is a vertical longitudinal section through a melting furnaceand taken substantially along the line l -I of Figure 2;

Figure 2 is a horizontal sectional view taken substantially along theline 2-2 of Figure l; and

' Figure 3 is a vertical cross section taken substantially along theline 33 of Figure 2, on an enlarged scale.

The melting furnace, as shown, is a gas or oil heated melting furnacebut may be in the form of electrical heating device. The molten metal iscarried on thefloor 1 of the furnace, bordered or surrounded by the facewalls 2 and the side walls 3 and closed at the top by a roof 4. Thefurnace is supported on both sides in bearings 5 located centrally inthe lower part and at right angles to the longitudinal axis of thefurnace. Beneath the floor, at both ends, are arranged eyes 6 to whichare hinged the piston rodslof hydraulically or pneumatically operatedpressure devices 8. The other end of each of the pressure devices 8 ishinged at 9.

A vertical feed chamber 10 is disposed in substantially the same planeas the rocking axis of the bearings 5. The feed chamber 10 is closed offfrom the inside of the melting furnace and only communicates with thefused metal through openings 11 below the level 12 of the fused metal.By means of a separating wall 14, connected with the curved wall 13 ofthe feed chamber 10 and the other side wall 3 of the furnace, theinterior of the furnace is divided into two melting chambers 15. Thesemelting chambers 15 communicate with each other through the openings 11so as to insure the level of molten metal being the same in the feedchamber 10 as is in the chambers 15.

The furnace is heated by burners 16, arranged in the face walls 2, whichheat the corresponding melting chambers .15. It will be noted that theheating means 16 are spaced or separated from the feed chamber,. so thatthe fresh material is not brought into contact with the burners of thehot waste gases, but continuously mixes with the molten metal as thelatter moves from one melting chamber to the other. By means of thecloseable openings 17 arranged in the face Walls 2, there may be appliedto the surface of the molten metal a layer or covering in the form of apurifying salt which serves geva oa to isolate the molten metal from thecombustion gases and prevent its burning or calcination. Spaced levers30 are pivotally mounted as at 31 to brackets 32 on top of the furnacebody 1. Adjustable counterweight members 33 are slidablymounted on thelever '30. Each of the levers 30 is also formed with a segmental portion3.4 which is operatively 'conriectedby any suitable means to a door (notshown) for closing each'of the openings 17. The exhaust gases passthrough a vertical channel 19 arranged in the separating wall 14 and awidened exhaust hood 20 arranged above the top 4 of thefurnace to thechimney.

' The material to be melted is supplied to the feed chamber through acloseable opening 21. In the feed chamber 10, above this feed opening,is arranged a dipping device 22 which is connected with a rod 23 passingthrough the roof of the furnace and is operated by a lever pull 24.After the material to be melted is 'fed into the chamber 10, thedippingdevice 22 is'lowered so that the material fed into the feedchamber and is pressed or forced under the molten metal to be thoroughlymixed with the same.

By the alternate actuation, preferably at regular intervals of time, ofthe pressure members or devices 8, the furnace is rocked in oppositedirections, as shown by dot-and-dash lines in Figure 1. During thisrocking movement, the molten metal flows from one melting chamberthrough the openings 11 and the feed chamber 10, into the other meltingchamber 15. Thereby, the material, freshly brought into the feed chamber10, is continuously washed or preheated by the hot liquid material inthe two melting chambers 15, which is subjected to the heating action ofthe spaced burners 16.

In this way, the fresh or cold material fed into the furnace is quicklymelted without being exposed to the direct contact with the hotcombustion gases or flames in the melting chambers.

The frequency of the rocking or tilting movement is suitably adjusted tothe amount of heat necessary for the melting of the material, and may becontrolled by the heat of the molten metal, and independently of thevolume of molten metal.

In a side wall 3 of the furnace, there is an opening forming a chamber25 through which, if necessary, large waste material may be introducedinto the furnace and which would not go into the feed chamber 10. Thefeed chamber 25 is heated by a burner 26 arranged in the side wall ofthe opening 25. Spaced stop members may be positioned so as to engagethe bottom of the furnace 1 in order to limit the downward rockingmovement thereof.

By means of a closeable casting nozzle 27 arranged in a face wall 2, apart of the molten material is fed into a casting pit, not shown in thediagrams, at certain intervals of time, after removal of the sealing andwhen tipped towards this side.

Thus, it will be seen that an improved and efiicient method of meltingmetal'and the like in an oscillating furnace is provided, in which thefresh material is constantly mixed with the molten metal as the latteris alternately transferred from one melting chamber to another andwithout subjecting the fresh material to either the heating flame or thehigh temperatures of the waste gases in the furnace. Further, the moltenmetal in the furnace may b'e'subjectedto'the action of a purifying salt,that forms a layer or covering for preventing the burning of the moltenmaterial by the combustion gases.

We claim:

1. The herein described method of melting metal in two spaced chambershaving a communicating passage therebet'ween, which consists in heatingeach of the chambers, simultaneously rocking the chambers in the samedirection, and continuously feeding fresh material into the passagecommunicating with the chambers so that the molten material alternatelypasses from one chamber to the other and the fresh' material iscontinuously mixed with the moltenmaterial as the latter moves from onechamber to the other so as to preheat the fresh material.

2. An improved method of melting material in a tiltable furnace ascalled for in claim 1 which includes the additional step of dipping the.fresh material under the molten material as the latter passes throughthe communicating passage so as to insure intimate contact therewith.

3. Animproved method of melting metals in a tiltable furnace as calledfor in claim 1 which includes the additional step of covering the moltenmaterial in the chambers with a layer of purifying salt.

' 4. An improved method of melting metal as called for in claim 3 whichincludes the additional step of withdrawing a portion of the moltenmaterial-from the chambers at predetermined intervals.

References Cited in the file of this patent UNITED STATES PATENTS

